PokemonGo
There's a small workaround to get a player's desired Eevee evolution in Pokemon Go. The Pokemon Company

Getting an Eevee to evolve the way you want it to in “Pokemon Go” may actually have a rather surefire way to accomplish. Reddit users have shared the trick, stating that this harks back to the original Pokemon anime to force the right Eeveelution.

As per the original Reddit thread, the key is to name a player’s Eevee with the nickname of the brother older brother who owned a particular Eevee. Doing so will let the player get an Eeveelution owned by that particular brother.

“It would seem that there is in fact a way to force an evolution of your Eevee. The Eevee Brothers from the original anime were named Rainer, Pyro, Sparky and they owned a Vaporeon, Flareon and Jolleon respectively,” said the Reddit post.

Based on the response on the thread, several people have been reporting success for this method. Updates from the original thread poster had also suggested that some people who had tried the new technique may not necessarily get the same desired Eevee evolution a second time.

Some people have reported that while the first Eevee evolved accordingly, the second did not follow through. One theory circulating about this particular topic is that “Pokemon Go” players may only be able to obtain one specific Evolution at a time.

One Redditor commented on the topic and suggested a way to solve the issue of evolution variations following the first Eevee. Reddit user DatapawWolf theorised that there may be a delay in the way the servers store the nickname. Because of this delay, the server may be performing a different function on the Eevee, so it turns out a different evolution once the player hits Evolve.

To go around this, players may want to try restarting their games after renaming the Eevee. This should be done before evolving the Pokemon, just as a precaution method to avoid any other factors that may influence the technique. So far, the results for the restarting technique have been missed.

One Reddit user attested to doing the technique six times, with a hundred percent success. Another tried the technique twice, though he was only successful on the first run.